Retention System

ABSTRACT

A retention assembly has a carbide bolster with a first and second segment brazed together, each segment forming at least part of a cavity formed of the bolster. A shaft has an inserted end is interlocked within the cavity.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/135,654 which is a continuation of U.S. patent application Ser. No.12/135,595 which is a continuation-in-part of U.S. patent applicationSer. No. 1212/112,743 which is a continuation-in-part of U.S. patentapplication Ser. No. 12/051,738 which is a continuation-in-part of U.S.patent application Ser. No. 12/051,689 which is a continuation of U.S.patent application Ser. No. 12/051,586 which is a continuation-in-partof U.S. patent application Ser. No. 12/021,051 which is acontinuation-in-part of U.S. patent application Ser. No. 12/021,019which was a continuation-in-part of U.S. patent application Ser. No.11/971,965 which is a continuation of U.S. patent application Ser. No.11/947,644, which was a continuation-in-part of U.S. patent applicationSer. No. 11/844,586. U.S. patent application Ser. No. 11/844,586 is acontinuation-in-part of U.S. patent application Ser. No. 11/829,761.U.S. patent application Ser. No. 11/829,761 is a continuation-in-part ofU.S. patent application Ser. No. 11/773,271. U.S. patent applicationSer. No. 11/773,271 is a continuation-in-part of U.S. patent applicationSer. No. 11/766,903. U.S. patent application Ser. No. 11/766,903 is acontinuation of U.S. patent application Ser. No. 11/766,865. U.S. patentapplication Ser. No. 11/766,865 is a continuation-in-part of U.S. patentapplication Ser. No. 11/742,304. U.S. patent application Ser. No.11/742,304 is a continuation of U.S. patent application Ser. No.11/742,261. U.S. patent application Ser. No. 11/742,261 is acontinuation-in-part of U.S. patent application Ser. No. 11/464,008.U.S. patent application Ser. No. 11/464,008 is a continuation-in-part ofU.S. patent application Ser. No. 11/463,998. U.S. patent applicationSer. No. 11/463,998 is a continuation-in-part of U.S. patent applicationSer. No. 11/463,990. U.S. patent application Ser. No. 11/463,990 is acontinuation-in-part of U.S. patent application Ser. No. 11/463,975.U.S. patent application Ser. No. 11/463,975 is a continuation-in-part ofU.S. patent application Ser. No. 11/463,962. U.S. patent applicationSer. No. 11/463,962 is a continuation-in-part of U.S. patent applicationSer. No. 11/463,953. The present application is also acontinuation-in-part of U.S. patent application Ser. No. 11/695,672.U.S. patent application Ser. No. 11/695,672 is a continuation-in-part ofU.S. patent application Ser. No. 11/686,831. All of these applicationsare herein incorporated by reference for all that they contain.

BACKGROUND OF THE INVENTION

In the road construction and mining industries, rocks and pavement aredegraded using attack tools. Often, a drum with an array of attack toolsattached to it may be rotated and moved so that the attack tools engagea paved surface or rock to be degraded. Because attack tools engagematerials that may be abrasive, the attack tools may be susceptible towear.

U.S. Pat. No. 6,733,087 to Hall et al., which is herein incorporated byreference for all that it contains, discloses an attack tool for workingnatural and man-made materials that is made up of one or more segments,including a steel alloy base segment, an intermediate carbide wearprotector segment, and a penetrator segment comprising a carbidesubstrate that is coated with a super hard material. The segments arejoined at continuously curved interfacial surfaces that may beinterrupted by grooves, ridges, protrusions, and posts. At least aportion of the curved surfaces vary from one another at about their apexin order to accommodate ease of manufacturing and to concentrate thebonding material in the region of greatest variance.

Examples of degradation assemblies from the prior art are disclosed inU.S. Pat. No. 6,824,225 to Stiffler, US Pub. No. 20050173966 toMouthaan, U.S. Pat. No. 6,692,083 to Latham, U.S. Pat. No. 6,786,557 toMontgomery, Jr., US. Pub. No. 20030230926, U.S. Pat. No. 4,932,723 toMills, US Pub. No. 20020175555 to Merceir, U.S. Pat. No. 6,854,810 toMontgomery, Jr., U.S. Pat. No. 6,851,758 to Beach, which are all hereinincorporated by reference for all they contain.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the invention a retention assembly has a carbidebolster comprising a cavity formed in its base end. A shaft comprises aninserted end disposed within the cavity. The shaft is disposed within ahollow shank which comprises a first end contacting the bolster and aloaded end in mechanical communication with the shaft and the insertedend is brazed to an inner surface of the cavity.

The shaft may be in mechanical communication with the loaded end througha threaded nut. The threaded nut may engage a shoulder of the shank. Thebrazed joint may comprise a braze material comprising copper, brass,lead, tin, silver or combinations thereof. The inserted end of the shaftmay be interlocked inside the cavity. The shaft, the carbide bolster andthe shank may be coaxial. The inserted end of the shaft may be brazedwith the inner surface of the cavity of the bolster. The inserted end ofthe shaft may be adapted to compliment the ceiling of the bolster. Thecavity may comprise a concave surface adapted to receive the shaft. Theretention assembly may be incorporated into drill bits, shear bits, conecrushers, picks, hammer mills or combinations thereof. The cavity of thebolster may comprise a thermal expansion relief groove. The interfacebetween the inserted end of the shaft and the bolster may be non-planar.The inserted end of the shaft may comprise a 1 to 15 degree taper. Theinserted end of the shaft may comprise at least one thermal expansionrelief groove. The thermal expansion relief grooves in the inserted endof the shaft may be adapted to receive the thermal expansion reliefgrooves in the cavity of the bolster. The inserted end of the shaft maybe brazed to a top of the cavity. A tip made of carbide and diamond maybe brazed to the bolster. An insert may be brazed into the cavity andthe insert may retain the inserted end of the shaft. The insert and theinserted end may comprise a rounded interface. The retention assemblymay be incorporated into a driving mechanism, a drum, a chain, orcombinations thereof. The bolster may comprise an assembly brazed intothe cavity and the assembly may comprise a pocket adapted to hold theinserted portion of the shaft.

In another aspect of the invention a retention assembly has a carbidebolster comprising a cavity formed in its base end. A shaft comprises aninserted end disposed within the cavity. The shaft is disposed within ahollow shank which comprises a first end contacting the bolster and aloaded end in mechanical communication with the shaft and the insertedend is interlocked within the geometry of the cavity by a casting.

The cast material may comprise metals like zinc, aluminum, magnesium;thermosetting plastics, Bakelite, melamine resin, polyester resin,vulcanized rubber or combination thereof. The shaft may be in mechanicalcommunication with the loaded end through a threaded nut. The threadednut may engage a shoulder of the shank. The inserted end of the shaftmay comprise a 1 to 15 degree taper. The inserted end of the shaft maycomprise an increase in diameter. The shaft, the carbide bolster and theshank may be coaxial. The inserted end of the shaft may compromise atleast one groove formed in its surface. The retention assembly may beincorporated into drill bits, shear bits, hammer mills, cone crushers,or combinations thereof.

The inserted end of the shaft may compromise a shaft geometry adapted tointerlock with the casting. The inner surface of the cavity of thebolster may comprise a cavity geometry adapted to interlock with thecasting. The cavity geometry may comprise a taper narrowing towards anopening of the cavity formed in the base end. The diameter of theopening of the cavity formed in the base end is slightly smaller thanthe diameter of a tapered end of the shaft. The cavity geometry maycomprise a lip. The inserted end of the shaft may be in contact with thecavity of the bolster. A tip of carbide and diamond may be brazed to thebolster. The retention assembly may be incorporated into a drivingmechanism, a drum, a chain, a rotor, or combination thereof. The castingmay submerge at least the tapered end of the shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional diagram of an embodiment of a plurality ofpicks suspended underside of a pavement milling machine.

FIG. 2 is a cross-sectional diagram of an embodiment of a pick

FIG. 3 is an exploded diagram of an embodiment of a pick.

FIG. 4 is a cross-sectional diagram of an embodiment of a pick.

FIG. 5 is a cross-sectional diagram of another embodiment of a pick.

FIG. 6 is a cross-sectional diagram of another embodiment of a pick.

FIG. 7 is a cross-sectional diagram of another embodiment of a pick.

FIG. 8 is a cross-sectional diagram of another embodiment of a pick.

FIG. 9 is a cross-sectional diagram of another embodiment of a pick.

FIG. 10 is a cross sectional diagram of an embodiment of an insertbrazed in a cavity.

FIG. 11 is a perspective diagram of another embodiment of an insertbrazed in the cavity.

FIG. 12 is a cross-sectional diagram of another embodiment of a pick.

FIG. 13 is a cross-sectional diagram of an embodiment of a castingprocess.

FIG. 14 is a cross-sectional diagram of another embodiment of a pick.

FIG. 15 is a cross-sectional diagram of another embodiment of a pick.

FIG. 16 is a cross-sectional diagram of another embodiment of a pick.

FIG. 17 is a cross-sectional diagram of another embodiment of a pick.

FIG. 18 is a cross-sectional diagram of an embodiment of a retentionassembly.

FIG. 19 is a cross-sectional diagram of another embodiment of a pick.

FIG. 20 is a cross-sectional diagram of another embodiment of a pick.

FIG. 21 is a cross-sectional diagram of another embodiment of a pick.

FIG. 22 is a cross-sectional diagram of another embodiment of a pick.

FIG. 23 is a cross-sectional diagram of another embodiment of a pick.

FIG. 24 is a cross-sectional diagram of another embodiment of a pick.

FIG. 25 is a cross-sectional diagram of another embodiment of a pick.

FIG. 26 is a cross-sectional diagram of another embodiment of a pick.

FIG. 27 is a cross-sectional diagram of another embodiment of a pick.

FIG. 28 is a cross-sectional diagram of another embodiment of a pick.

FIG. 29 is a cross-sectional diagram of another embodiment of a pick.

FIG. 30 is a cross-sectional diagram of an embodiment of a trencher.

FIG. 31 is a cross-sectional diagram of another embodiment of atrencher.

FIG. 32 is a cross-sectional diagram of an embodiment of a percussionbit.

FIG. 33 is a cross-sectional diagram of an embodiment of a fixed cutterbit.

FIG. 34 is a cross-sectional diagram of an embodiment of a roller cone.

FIG. 35 is a cross-sectional diagram of another embodiment of aretention assembly.

FIG. 36 is a cross-sectional diagram of another embodiment of aretention assembly

FIG. 37 is a cross-sectional diagram of another embodiment of aretention assembly

DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT

It will be readily understood that the components of the presentinvention, as generally described and illustrated in the Figures herein,may be arranged and designed in a wide variety of differentconfigurations. Thus, the following more detailed description ofembodiments of the methods of the present invention, as represented inthe Figures is not intended to limit the scope of the invention, asclaimed, but is merely representative of various selected embodiments ofthe invention.

The illustrated embodiments of the invention will best be understood byreference to the drawings, wherein like parts are designated by likenumerals throughout. Those of ordinary skill in the art will, of course,appreciate that various modifications to the methods described hereinmay easily be made without departing from the essential characteristicsof the invention, as described in connection with the Figures. Thus, thefollowing description of the Figures is intended only by way of example,and simply illustrates certain selected embodiments consistent with theinvention as claimed herein.

FIG. 1 is a cross-sectional diagram of an embodiment of a plurality ofpicks 101 attached to a rotating drum 102 connected to the underside ofa pavement milling machine 103. The milling machine 103 may be a coldplaner used to degrade man-made formations such as pavement 104 prior tothe placement of a new layer of pavement. Picks 101 may be attached tothe drum 102 bringing the picks 101 into engagement with the formation.

FIG. 2 is an orthogonal diagram of an embodiment of a pick 101. The pick101 comprises a cemented metal carbide bolster 201 attached to a hollowshank 202 at a carbide base 203 of the bolster 201. The carbide bolster201 may comprise tungsten carbide, calcium carbide, silicon carbide,cementite, boron carbide, tantalum carbide, titanium carbide orcombination thereof. The shank 202 may be substantially cylindricaland/or tapered. The impact tip 205 may comprise a super hard material207 bonded to a carbide substrate at a non-planar interface. Preferablythe carbide substrate has an axial thickness less than 6 mm. In someembodiments, the carbide substrate ranges between 10 and 1 mm. Thesuperhard material may be at least 0.100 inches thick axially, in someembodiments it may be over 0.250 inches. The superhard material may beformed in a substantially conical shape.

The super hard material 207 may comprise diamond, polycrystallinediamond with a binder concentration of 1 to 40 weight percent, cubicboron nitride, refractory metal bonded diamond, silicon bonded diamond,layered diamond, infiltrated diamond, thermally stable diamond, naturaldiamond, vapor deposited diamond, physically deposited diamond, diamondimpregnated matrix, diamond impregnated carbide, monolithic diamond,polished diamond, course diamond, fine diamond, nonmetal catalyzeddiamond, cemented metal carbide, chromium, titanium, aluminum, tungsten,or combinations thereof.

The impact tip 205 may comprise a carbide substrate 305 bonded to thesuper hard material 207. Typically the substrate of the impact tip 205is brazed to the carbide bolster 201 at a planar interface 306. The tip205 and the bolster 201 may be brazed together with a braze materialcomprising a melting temperature from 700 to 1200 degrees Celsius. Thesuper hard material 207 may be bonded to the carbide substrate 305through a high temperature high pressure process (HTHP).

A cavity 307 may be formed at the end base of the bolster 201. Aninserted end 204 of a shaft 301 may be inserted into the cavity 307. Theother end 250 of the shaft 301 may be in mechanical communication withthe loaded end 251 of the shank 202. The other end 250 of the shaft maycomprise at least one thread 252 adapted to receive the threaded nut302. The nut diameter may be bigger than the shaft diameter but smallerthan the shank diameter.

The inserted end 204 of the shaft 301 may be brazed within the cavity307 of the bolster 201. Preferably, the head of the inserted endcomprises a geometry that compliments the geometry of the cavity.Preferably, the head of the inserted end is brazed directly to a ceiling253 of the cavity. In other embodiments, the shaft is brazed to a sidewall of the cavity.

Referring now to FIG. 3, the substrate 305 and the bolster 201 may bebrazed together at high temperature at the same time the inserted end204 of the shaft 301 is brazed to the cavity 307. The shaft 301 and thecavity 307 may be brazed at a non-planar interface. In some embodiments,the braze joints may be brazed at different times. In some embodiments,both braze joints utilize substantially similar braze materials 410.After brazing the inserted end of the shaft into the cavity, the otherend of the shaft may be tensioned through the hollow shank and anchoredwhile under tension with the threaded nut. This tension loads the otherend of the hollow shank and snuggly holds the bolster against the hollowshank.

In FIG. 4, the inserted end 204 of the shaft 301 is tapered, which isadapted to abut a taper of the cavity. The shaft taper and the cavitytaper may be brazed together.

In the embodiment of FIG. 5, the inserted end 204 of the shaft 301 isbrazed to the ceiling 253 of the cavity 307. The diameter of theinserted end is larger than an opening constricted by a protruding lip601 formed in the cavity. The geometry of the inserted end is adapted toflex upon insertion and snap out once past the lip 601. The inserted end204 of the shaft 301 may be interlocked inside the cavity 307 of thebolster. The geometry of the inserted end 204 of the shaft 301 may allowenough space for thermal expansion while brazing the inserted end to thecavity.

Referring now to FIG. 6, the inserted end 204 of the shaft 301 maycomprise at least one relief groove 650 to allow space for thermalexpansion during brazing. This may reduce residual stress that maydevelop during brazing.

Referring now to FIG. 7, the ceiling 253 of the cavity 307 of thebolster 201 may comprise at least one relief groove 701 to allow forthermal expansion during brazing. They may reduce residual stress thatmay develop during brazing. The inserted end 204 of the shaft 301 may bepartially brazed with the ceiling 253 of the cavity 307 of the bolster201.

In FIG. 8 another embodiment of the invention is disclosed in which thepick 101 may comprise at least one groove 701 in the ceiling 253 of thecavity 307 of the bolster 201 adapted to receive protrusions in theinserted end 204 of the shaft 301. The ceiling 253 may be irregular andnon-planar. The grooves 701 may form an interlocking mechanism. Thegrooves 701 may increase the surface area of the inserted end 204 andceiling allowing a larger braze joint.

FIG. 9 is a cross-sectional diagram of another embodiment of the pick101. A relief opening 802 may be formed in the inserted end 204 of theshaft 301. The purpose of the opening 802 may be to allow enough spacefor thermal expansion while brazing.

Referring now to FIG. 10, an insert may be brazed into the cavity of thebolster. The insert may be adapted to retain the inserted end of theshaft, preferably in ball and socket type of joint, although in someembodiments the joint may be tapered or interlocked. A cap 505 may beused in some embodiment to prevent a brazing material from flowing intothe insert and interfering with the joint. The solidification of thebrazing material may restrict the compliancy of the joint during abending moment induced in the bolster while in operation and createstress risers. The insert and the inserted end 204 of the shaft maycomprise a rounded interface.

In FIG. 11, another embodiment of an inserted brazed within the cavityis shown.

FIG. 12 is a cross-sectional diagram of another embodiment of the pick101. The inserted end 204 of the shaft 301 may be interlocked within thecavity of the bolster 201 by casting. The casting may comprise zinc, abraze material, a plastic, lead, or combinations thereof. Zinc may bethe preferred casting material since zinc will not significantly bond tothe carbide and zinc demonstrates a high compressive strength. In someembodiment a non-wetting agent may be applied to the head of the shaftto prevent the zinc from forming a strong bond with the shaft.

In FIG. 13, a cross-sectional diagram of depicting a casting process.The tapered inserted end 204 of the shaft 301 may be brought into thecavity 307 and molten cast material 401 may be poured inside the cavity307. The molten cast material 401 may be left to be cooled and solidify.The cooling rate may vary according to the cast material. The rate atwhich a casting cools may affect its microstructure, quality andproperties of the casting and the mechanical interlocking of the castwith the shaft and the geometry of the cavity. The geometry of thecavity 307 of the bolster 201 may provide additional support in keepingthe inserted end 204 of the shaft 301 interlocked within the cavity 307.In other embodiments, casting material granules, balls, shavings,segments, dust or combinations thereof may be placed in the cavity withthe inserted end of the shaft and melted in place. The casting materialmay be heated in an oven, or a heating source such as a torch or radiantheater may be applied within the cavity or applied to the outside of thebolster.

FIG. 14 is an embodiment of the shaft casted within the cavity. Theshaft may comprise an increase in diameter adapted to substantiallycontact an inner diameter of the hollow shank.

FIG. 15 is a cross-sectional diagram of another embodiment of the pick101. The inserted end 204 of the shaft 301 may or may not touch theceiling 253 of the cavity. The casting may form around the entiresurface of the head of the inserted end.

In FIG. 16, the inserted end 204 of the shaft 301 may be tapered toincrease its surface area with the casting. In some embodiments, thetaper is gradual and distributes the load substantially equally acrossan interface between the casting and the inserted end. Another benefitof casting the shaft in place is distributing the loads acrosssubstantially the entire inner surface of the cavity.

Referring now to FIG. 17, the inserted end may comprise at least onegroove 1001, and may be tapered. The grooves 1001 may increase the gripbetween the inserted end and the casting.

FIG. 18 is a cross-sectional diagram of an embodiment of a degradationassembly inserted into a blind hole 2020 of a tool, such as a fixedcutter drill bit, percussion bit, roller cone bit, miller, crusherand/or mill. The inserted end of the shaft 301 may be brought togetherwith the cavity 307 of the bolster 201 by casting.

FIG. 19 is another embodiment of a pick 101. The bolster 201 comprises afirst and second segment 2000, 2001. Since carbide is a brittle materialand the shaft 301 is tensioned and therefore loading at least a portionof the carbide a thick carbide lip 2002 is incorporated into thisembodiment. The bolster 201 is formed in two segments to allow insertionof the bolster from the opposing end of the shaft. A diameter increaseof the inserted end 204 interlocks with the lip 2002 of the firstcarbide segment. The second segment of the bolster is brazed to thefirst after the inserted end is in place. Both segments are made ofsimilar materials reducing thermal stresses that are common intraditional picks. In some embodiments, the second carbide segment 2001overhangs the first segment 2000, directing debris away from the brazejoint 2005 during a milling operation. The interface between the lip ofthe cavity and the inserted end of the shaft in some embodiments forms ajoint that allows the inserted end to swivel within the cavity 307. Thisreduces the transfer of stress induced in the bolster during a bendingmoment to the shaft. In some embodiments, the shaft may be casted,brazed, bonded, or combinations thereof in the cavity after insertion.In some embodiments, the inserted end may be brazed in place while thebolster segments are brazed together. In other embodiments, the whilebrazing the segments together the flow of the braze material iscontrolled to prevent the braze material from inferring with the shaft.In some embodiments, the inserted end of the shaft is coated with boronnitride or another non-wetting agent to prevent the braze material frombonding to itself. In some embodiments, the segments may be made ofdifferent carbide grades. The first segment may comprise a more wearresistant carbide grade while the second segment may comprise a toughergrade or vice versa.

FIG. 20 discloses a rearward sloping braze joint 2006 between thecarbide segments, while FIG. 21 discloses a frontward sloping brazejoint 2007 between the carbide segments. FIG. 22 discloses a thirdbolster segment 2008.

In some embodiments, the space within the cavity may be lubricated. Onesuch embodiment is disclosed in FIG. 23 where a port 2009 is formed inthe shaft 301 to accommodate a flow of lubricate from a lubricantreservoir to the cavity 307. FIG. 24 discloses carbide segments bondedto another along an axial braze joint 2010. FIG. 25 disclosed a wearresistant coating 2011 deposited on the inserted end to prevent wear.FIG. 26 discloses a braze joint 2012 between the lip 2002 and underside2013 of the inserted end of the shaft.

FIGS. 27 and 28 both disclose embodiments where the bolster is adaptedto rotate around the inserted end of the shaft. In such embodiments, ano-ring 2014 may be place between the hollow shank and the base end ofthe bolster. The shaft may be press fit into the hollow shank. In someembodiments the shaft protrudes out of a solid shank. Wear resistantmaterial and lubricants may be applied to the rotating surfaces. In FIG.27, the shaft is press fit within the hollow shank. In FIG. 28, theshaft is tensioned and secured through a threaded nut 2015 on the loadedend. A hardened washer 2016 is attached to the hollow shank and abuttingthe base end of the bolster to provide a bearing surface on which thebolster may rotate. The bolster also forms an overhang 2017 over thehollow shank to direct debris away from the rotating interface 2018.

FIG. 29 is another embodiment of a segment bolster and the inserted end204 of the shank 301 is casted in place.

FIG. 30 is a perspective diagram of an embodiment of a pick on a rockwheel trenching machine 130 and FIG. 20 discloses an embodiment of thepick 101 on a chain trenching machine. The picks 101 may be placed on achain that rotates around an arm 1402 of a chain trenching machine 1401.

In FIG. 32, a cross-sectional diagram of an embodiment of a percussionbit 1400 having a bit body with slots for receiving the picks 101. Thepicks may be anchored in the slots through a press fit, barbs, hooks,snap rings, or combinations thereof. FIG. 33 discloses the picks in afixed cutter bit 1500 and FIG. 34 discloses the picks 101 in a cone 5004of a roller cone bit.

FIG. 35 is a cross-sectional diagram of another embodiment of theretention assembly. The retention assembly 2600 may be used to bring twoparts together such as two parts 2500 and 2501 of a chair.

Referring now to FIG. 25, the retention assembly 2006 may be used toconnect two blocks 5005 and 5006 together.

In FIG. 26 the retention assembly 2006 may be used to attach a block2601 with the other block 2602.

Whereas the present invention has been described in particular relationto the drawings attached hereto, it should be understood that other andfurther modifications apart from those shown or suggested herein, may bemade within the scope and spirit of the present invention.

1. A retention assembly, comprising: a carbide bolster comprising a first and second segment brazed together, each segment forming at least part of a cavity formed of the bolster; and a shaft comprising an inserted end is interlocked within the cavity.
 2. The assembly of claim 1, wherein the shaft is disposed within a hollow shank which comprises a first end contacting the bolster and a loaded end in mechanical communication with the shaft.
 3. The assembly of claim 1, wherein the shaft is adapted to rotate within an inner diameter of the hollow shank.
 4. The assembly of claim 1, wherein the first and second segment are brazed at a rearward sloping braze.
 5. The assembly of claim 1, wherein the first and second segment are brazed at a forward sloping braze.
 6. The assembly of claim 1, wherein the cavity is lubricated through a port formed in the shaft.
 7. The assembly of claim 1, wherein the segments are joined together through a substantially axial braze joint.
 8. The assembly of claim 1, wherein the inserted end is adapted to swivel within the cavity.
 9. The assembly of claim 1, wherein a braze non-wetting agent is applied to the surface of the inserted end.
 10. The assembly of claim 1, wherein the inserted end is brazed with to the cavity.
 11. The assembly of claim 1, wherein the inserted end is casted within the cavity.
 12. The assembly of claim 1, wherein the bolster is adapted to rotate about around the inserted end of the shaft which is rigidly secured within a hollow shank adapted for attachment to a driving mechanism.
 13. The assembly of claim 12, wherein a hardened washer is disposed between an interface between the hollow shank and the bolster.
 14. The assembly of claim 12, wherein the bolster forms an overhang over the hollow shank.
 15. The assembly of claim 12, wherein the shaft is press fit within the hollow shank.
 16. The assembly of claim 1, wherein the second segment forms an overhang over the first segment.
 17. The assembly of claim 1, wherein the assembly is adapted for attached to a pavement milling machine, trencher, a mining machine, or combinations thereof.
 18. The assembly of claim 1, wherein the assembly is adapted for attached to a drill bit, a fixed cutter bit, a roller cone bit, a percussion bit, or combinations thereof.
 19. The assembly of claim 1, wherein a tip comprising a carbide segment straight is bonded to the second carbide segment and sintered diamond is bonded to the carbide substrate.
 20. The assembly of claim 1, wherein the interface between the inserted end and the cavity forms a ball and socket joint. 